The cochlear nucleus is the terminus for all incoming auditory information to the brain and the origin of all central auditory pathways. In a general way, the role of the cochlear nucleus is to recode signals from the auditory nerve and to distribute the resultant messages to higher centers. The long term goal of this research is to understand the structural basis by which neural activity from the auditory nerve is "processed" in the cochlear nucleus. This effort requires a thorough knowledge of the synaptic organization in the cochlear nucleus because the coding process is hypothesized to be dependent on definable features of the relationship between pre- and postsynaptic neurons. The present proposal will apply intracellular recording and staining methods to reveal the structural and functional character of individual neurons, tract-tracing methods to reveal the source and distribution of input projections, and immunocytochemical techniques to identify molecules associated with neurotransmitter cell classes. These data will have direct relevance to ideas about excitation and inhibition in the cochlear nucleus and about how neural circuits act to shape the coding process.